This invention relates to a process for filling a muffler with fibrous material as well as a muffler filled with fibrous material.
U.S. Pat. No. 4,569,471 to Ingemansson et al. describes a process and apparatus for feeding lengths of a continuous glass fiber strand into a muffler outer shell. The apparatus includes a nozzle for expanding the fiber strand into a wool-like material before the material enters the outer shell. In a first embodiment, filling of an outer cylinder 14 of the muffler shell occurs without an end-piece joined to the outer cylinder 14. After the filling operation is completed, the outer cylinder 14 is moved to a separate station where the end piece is welded onto the outer cylinder 14. During movement of outer cylinder 14, a vacuum device may remain coupled to the outer cylinder 14 or a cover is placed over the filled outer cylinder 14 so as to prevent the wool-like material from coming out during transport, see column 4, lines 1-7. During the closure process, great care must be taken to ensure that glass fiber material does not extend into the joint area.
In a second embodiment, illustrated in FIG. 3, a perforated pipe/outer end piece assembly is positioned only part way into the muffler outer cylinder 14 during the glass material filling operation. After the filling operation has been completed, the perforated pipe/end piece assembly is moved to its final position within the outer cylinder 14.
There is a need for a muffler outer shell filling process which can be implemented using a closed muffler shell such that after a glass material filling operation has been completed, muffler shell components do not have to welded or otherwise joined together.
This need is met by the present invention, wherein a process is provided for filling a closed muffler shell with fibrous material through a fill opening provided in a perforated pipe extending at least part way through the muffler shell. Alternatively, an end of the perforated pipe may be positioned within the muffler shell a spaced distance from an opening in the shell such that the fibrous material is fed into the muffler shell via a gap defined between the perforated pipe end and a portion of the closed shell defining the opening.
In accordance with a first aspect of the present invention, a process is provided for filling a muffler with fibrous material. The process comprises the steps of: providing a muffler comprising a closed outer shell having an inner cavity and a first perforated pipe, the perforated pipe having a first end portion with at least one fill opening; and feeding fibrous material into the outer shell inner cavity through the at least one fill opening in the perforated pipe to form a fibrous product in the outer shell.
The fill opening may be formed via drilling, sawing, during the pipe forming process via a molding or stamping process or via any other conventional process for forming an opening in a pipe.
The feeding step may comprise the steps of: providing a nozzle; feeding continuous strand material and pressurized air into the nozzle such that a wool-type product emerges from the nozzle; and positioning the nozzle adjacent to or in the fill opening such that the wool-type product is fed into the outer shell inner cavity.
The continuous strand material comprises one more strands each comprising a plurality of glass filaments which may be selected from the group consisting of E-glass filaments and S-glass filaments. Preferably, the continuous strand material comprises an E-glass roving sold by Owens Corning under the trademark ADVANTEX(copyright) or an S-glass roving sold by Owens Corning under the trademark Zentron(copyright).
In one embodiment, the perforated pipe may comprise a second end portion and the process may further comprise the step of drawing a partial vacuum in the outer shell inner cavity through the second end portion of the pipe during the feeding step.
In another embodiment, the muffler further comprises a second perforated pipe having an end portion, and the process further comprises the step of drawing a partial vacuum in the outer shell through the end portion of the second pipe during the feeding step.
The second perforated pipe may further include at least one fill opening in its end portion and the process additionally comprises the step of feeding fibrous material into the outer shell inner cavity through the at least one fill opening in the second perforated pipe. The process may further comprise the step of drawing a partial vacuum in the outer shell through the first end portion of the first pipe during the step of feeding fibrous material through the at least one fill opening in the second perforated pipe.
The first perforated pipe may comprise two or more fill openings and the fibrous material is fed into the outer shell inner cavity through the two or more fill openings. Feeding of the fibrous material through the two or more fill openings may occur sequentially or concurrently.
The perforated pipe preferably has a plurality of first openings of a first dimension which define the perforations in the pipe. The at least one fill opening may have a second dimension which is greater in size than the first dimension.
In accordance with a second aspect of the present invention, a process is provided for filling a muffler with fibrous material. The process comprises a first step of providing a muffler comprising a closed outer shell having an inner cavity and a first perforated pipe. The perforated pipe has a first end spaced from an opening in a first sidewall of the outer shell. A portion of the outer shell defining the first sidewall opening and the first pipe end define a gap therebetween. A second step comprises feeding fibrous material into the outer shell inner cavity through the gap to form a fibrous product in the outer shell.
The feeding step may comprise the steps of: providing a nozzle; feeding continuous strand material and pressurized air into the nozzle such that a wool-type product emerges from the nozzle; and positioning the nozzle adjacent to or in the gap such that the wool-type product is fed into the outer shell inner cavity.
In accordance with a third aspect of the present invention, a muffler is provided comprising a closed outer shell inner cavity, and a first perforated pipe extending at least part way through the closed outer shell. The perforated pipe has an end portion provided with at least one first fill opening adapted to receive fibrous material.
The muffler may further comprise a second perforated pipe having an end portion with at least one second fill opening. The muffler outer shell may comprise at least one internal partition for defining first and second internal compartments in the outer shell inner cavity. The first internal compartment is adapted to receive fibrous material through the at least one first fill opening and the second internal compartment is adapted to receiving fibrous material through the at least one second fill opening.
In accordance with a fourth aspect of the present invention, a muffler is provided comprising a closed outer shell having an inner cavity, a first perforated pipe extending through the closed outer shell, and fibrous material in the outer shell defining a fibrous product in the outer shell. The perforated pipe has an end portion provided with at least one first fill opening. The fibrous material entered into the outer shell inner cavity through the at least one fill opening.
The muffler may further comprise a second perforated pipe having an end portion with at least one second fill opening. The muffler outer shell may include at least one internal partition for defining first and second internal compartments in the outer shell inner cavity. The first internal compartment has fibrous material fed through the at least one first fill opening and the second internal compartment has fibrous material fed through the at least one second fill opening.
It is contemplated that the muffler outer shell may have at least two internal partitions defining first, second and third internal compartments in the outer shell inner cavity. The first internal compartment has fibrous material fed through the at least one first fill opening, the second internal compartment has fibrous material fed through the at least one second fill opening, and the third internal compartment is positioned between the first and second compartments and has substantially no fibrous material therein.